Review of What Bugged the Dinosaurs? Insects Disease and Death in the Cretaceous

by George Poinar, Jr., and Roberta Poinar

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One hundred million years ago, a female sand fly settled on a sauropod for what turned out to be her final blood meal. Something startled the dinosaur, and the insect's dining was interrupted. She escaped the thrashing beast only to become trapped in the sticky resinous sap of an araucarian tree.

Her "straining, desperate movements attracted the attention of a small predator patrolling the bark, who nipped open a minuscule hole in the end of her abdomen, deftly pulled out the reproductive system, and devoured the protein-rich eggs. Some of the gut contents of the entrapped insect spilled out onto the fresh resin as life ebbed away. She lay on one side in a drop of spilled blood, disemboweled, head and mouthparts clearly visible, wings outstretched.... An additional resin flow entombed the small female fly" in what we now call Burmese amber.

Of the many large and small dramas of Cretaceous life that Oregon State University Zoology Professor George Poinar, Jr., and retired research scientist Roberta Poinar vividly recount in What Bugged the Dinosaurs?, this one is the most significant. For when the Poinars studied that remarkably well-preserved ancient event in their laboratory, they discovered that the dinosaur blood was infected with a pathogenic microorganism.

Had the fly survived to bite another beast, it might well have passed the disease along, much as insect-borne diseases are spread from animal to animal today. That is not the only way insects bugged dinosaurs. They often competed for the same food or were irritating biters, stingers, and parasites.

Of course, they had their beneficial traits as well. They were pollinators of plants that fed herbivorous dinosaurs. They were food for carnivorous dinosaurs or the animals on which they fed. They were the "Sanitary Engineers of the Cretaceous," playing a major role in the recycling the nutrients in dung and the vital chemicals in the bodies of dead animals and plants.

In natural history museums, plodding, hulking herbivorous dinosaurs and their fierce carnivorous cousins command the public's attention. Few visitors pay attention to the smaller reptiles, amphibians, and mammals of the Mesozoic Age (that includes the Triassic, Jurassic, and Cretaceous Periods).

Even fewer consider the plants and insects that comprised the largest part of the ecosystem. Almost no one thinks about the disease-causing bacteria, parasites, and symbionts whose interaction with dinosaurs probably drove their mutual evolution faster than changing climate and geography.

What Bugged the Dinosaurs? is the Poinars' attempt to remedy those oversights. They assert that it is impossible to describe life in the Cretaceous Period without paying particular attention to insects.

The book deftly guides readers through the science essential to that understanding. Their prose puts readers on the scene when fossils form in rocks and amber, when plate tectonics reshape the arrangement of continents, when species and ecologies evolve, and when individual creatures thrive, compete, ail, suffer, and die.

Chapter by chapter, the authors introduce a wide range of insect species that bite, swarm, irritate, and even take up residence within and on the dinosaurs that readers know so well. They draw their stories from the fossil record, especially the amber of their expertise, comparing Cretaceous insects with their present-day descendents.

After discovering the ancient ecology, readers follow the authors into the laboratory where they analyze delicate evidence in the form of magnificent color images. Finally it is time to interpret findings and draw conclusions. While acknowledging that an asteroid impact brought a catastrophic end to the Cretaceous and the dinosaurs (at least the non-avian ones), the Poinars question whether the great reptiles may have already been in serious decline.

Had disease, parasitic infestation, and competition with insects already set them on a path toward extinction? That is not a new question, but it remains an important one in paleontology. It is the kind of question that continues to inspire scientists and readers alike.

The Poinars' answer to that question is yes, but they make sure their readers know that the conclusion is less important than the open issues that remain.

Scientists relish unexpected discoveries like the unfortunate insect in the Poinars' amber sample. Readers who love paleontology will feel the same way about this remarkable book, savoring its fascinating trove of questions and knowledge about the insects that bugged the dinosaurs.